On Tue, Feb 10, 2015 at 06:26:34PM -0800, Mark Brown wrote: > On Sun, Feb 08, 2015 at 10:45:11PM -0800, Kenneth Westfield wrote: > > On Sat, Feb 07, 2015 at 06:32:29AM +0800, Mark Brown wrote: > > > > I'd really like to see some discussion as to how this is all supposed > to > > > be handled - how will these direct hardware access drivers and device > > > trees work when someone does want to use the DSP (without causing > > > problems), and how will we transition from one to the other. This is > > > particularly pressing if there are use cases where people will want to > > > switch between the two modes at runtime. > > > > What I'm trying to avoid here is being in a situation where we have > > > existing stable DT bindings which we have to support but which > conflict > > > with the way that people want to use the systems. > > > The ipq806x SOC has no LPASS DSP. On SOCs with a DSP, these drivers > > would not be enabled. > > OK, but I'm guessing that they're using the same IP that is in other > SoCs which do have the DSP so even if you don't care for this device it > might still be an issue. > > > These drivers are prefixed with "lpass" to differentiate themselves from > > other drivers that would interact with a DSP, rather than the LPASS > > hardware directly. > > Right, it may be that all that's needed here is some indication as to > how to describe a system which *does* have a DSP. Perhaps require that > the devices be children of the DSP, that way if people want to access > the hardware directly they can load a dummy driver for the DSP that just > passes things through if they don't want to use the DSP? Replacing DSP-based drivers with LPASS-based drivers would be something that should be handled by Kconfig selections. For the DT, the DSP-related nodes and the LPASS-related nodes shouldn't overlap. There should be a DSP-based DT binding and a separate LPASS-based DT binding. Tying one or the other to the sound node (but not both), should work. -- Kenneth Westfield Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
